Subject: Re: [mpls] [PWE3] 1588 over MPLS draft
From: "Shahram Davari" <[email-masked]>
To: "Mach Chen" <[email-masked]>, "S. Davari" <[email-masked]>, "Jia HE" <[email-masked]>
Cc: "[email-masked]" <[email-masked]>, "[email-masked]" <[email-masked]>, "[email-masked]" <[email-masked]>, "[email-masked]" <[email-masked]>
Date: Wed, 14 Jul 2010 10:58:52 -0700
List-Id: Multi-Protocol Label Switching WG <mpls.ietf.org>

Hi Mach,

When a service provider wants to create these PTP LSPs, what is wrong with allocating a range of labels for this purpose? This is purely a software exercise. There are 2 million labels available to each node, why can't some of them be allocated by software to PTP?

In theory what you say is correct and should work, but in practice there is a function called 1-step Transparent clocking that requires time stamping at the PHY (immediately when the packet is received or transmitted). PHY chips don't have CAM or lots of memory to store a few thousand random labels. The label range will solve that problem and is consistent with MPLS architecture.

Thanks,
Shahram

-----Original Message-----
From: Mach Chen [mailto:[email-masked]] 
Sent: Wednesday, July 14, 2010 1:53 AM
To: S. Davari; Jia HE; Shahram Davari
Cc: [email-masked]; [email-masked]; [email-masked]; [email-masked]
Subject: Re: [mpls] [PWE3] 1588 over MPLS draft

Hi Shahram,

From the view of implementation, there is no more difference between SHOULD 
and MUST :-)
For me, the Label Range is more like a mechanim to notify related nodes that 
some LSPs are dedicated for PTP messages other than the chips memory 
limitation, because the memory restriction is always there whatever you use 
Label Range or not.
IMHO, since the objective is to tell related MPLS nodes which LSPs are PTP 
LSPs, an indication in the signaling(RSVP-TE/GMPLS/LDP) is enough and seems 
more common. And it will avoid the strict requirement of "the network and 
all nodes required to support the Label range".
In addition, there should be some mechanims(e.g., ISIS/OSPF extensions) for 
nodes to advertise their PTP capability hence to help PTP LSPs computation.

Best regards,
Mach

--------------------------------------------------
From: "S. Davari" <[email-masked]>
Sent: Wednesday, July 14, 2010 2:31 PM
To: "Jia HE" <[email-masked]>; "Shahram Davari" <[email-masked]>
Cc: <[email-masked]>; <[email-masked]>; <[email-masked]>; <[email-masked]>
Subject: Re: [mpls] [PWE3] 1588 over MPLS draft

> Hi Jia,
>
> Label range is a SHOULD requirements and not MUST. The reason for Label 
> Range is
> mainly for PHY chips that don't have large memory and can't store a lot of
> Labels. Otherwise the PTP LSP is setup via signaling that specifies the 
> LSP as
> carrying 1588.
>
> So the answer is that if a Label range is used it must be a Global range 
> within
> a network and should not be used by any router for other applications.
>
> Thanks,
> Shahram
>
>
>
> ________________________________
> From: Jia HE <[email-masked]>
> To: Shahram Davari <[email-masked]>
> Cc: [email-masked]; [email-masked]; [email-masked]; [email-masked]
> Sent: Tue, July 13, 2010 9:50:37 PM
> Subject: Re: [mpls] [PWE3] 1588 over MPLS draft
>
>
> Hi Shahram,
>
> One question about "PTP Label Range":
>
> To my knowledge, label in MPLS network is a local  matter. For example, we 
> may
> have per-interface or per-platform label space. Will  this specificed "PTP 
> Label
> Range" conflict with the current in-use labels  for common LSPs?
>
>
> B.R.
> Jia
>
> ----- Original Message ----- 
>>From: Shahram    Davari
>>To: [email-masked] ; [email-masked] ; [email-masked] ; [email-masked]
>>Sent: Thursday, July 08, 2010 3:12 AM
>>Subject: [PWE3] 1588 over MPLS draft
>>
>>
>>Hi All,
>>
>>Please find attached our first draft of 1588 over MPLS.    Since we have 
>>some
>>technical issues converting the Word format to Txt we    couldn’t  upload 
>>the
>>draft before the cut-off date. However we will    present the draft in the 
>>next
>>IETF meeting and will upload the draft after the    meeting.
>>
>>Note that the main WG is TicToc but may require    consultation with MPLS 
>>and
>>PWE3 WGs.
>>
>>Thanks,
>>Shahram Davari
> ________________________________
> _______________________________________________
>>pwe3 mailing    list
>>[email-masked]
>>https://www.ietf.org/mailman/listinfo/pwe3
>>
>
>

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